Nonsense-mediated mRNA decay in humans at a glance.

Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA.

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Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA lynne_maquat@urmc.rochester.edu.

Abstract

Nonsense-mediated mRNA decay (NMD) is an mRNA quality-control mechanism that typifies all eukaryotes examined to date. NMD surveys newly synthesized mRNAs and degrades those that harbor a premature termination codon (PTC), thereby preventing the production of truncated proteins that could result in disease in humans. This is evident from dominantly inherited diseases that are due to PTC-containing mRNAs that escape NMD. Although many cellular NMD targets derive from mistakes made during, for example, pre-mRNA splicing and, possibly, transcription initiation, NMD also targets ∼10% of normal physiological mRNAs so as to promote an appropriate cellular response to changing environmental milieus, including those that induce apoptosis, maturation or differentiation. Over the past ∼35 years, a central goal in the NMD field has been to understand how cells discriminate mRNAs that are targeted by NMD from those that are not. In this Cell Science at a Glance and the accompanying poster, we review progress made towards this goal, focusing on human studies and the role of the key NMD factor up-frameshift protein 1 (UPF1).